We present a microfluidic chemical/biological sensor based on dissolvable membranes incorporating gold
nanoparticles. The presence of the target analyte in a fluidic sample being assayed dissolves the membrane,
causing the change in its optical absorption. To enhance the contrast between the membrane and the fluidic sample,
the membranes are chemically treated to exhibit strong absorption at certain wavelengths. Here, we use
N,N'-cystaminebisacrylamide (CBA) cross-linked poly(acrylamide) (PAAm) membranes dissolved by a sample
solution containing dithioerythritol (DTT) to demonstrate this approach. The dissolvable membrane incorporates
gold nanoparticles to exhibit strong absorption at 572nm.